Charged internal combustion engine

ABSTRACT

A charged internal combustion engine ( 1 ) having at least one stage of charging by a turbocharger ( 3 ), in which at least one supplemental compressor ( 4 ) is connected parallel to or in series with the turbocharger, and in which the supplemental compressor ( 4 ) has a drive independent from the working medium cycle of the internal combustion engine.

RELATED APPLICATIONS

The present application is a division of U.S. patent application Ser.No. 09/836,787, filed on Apr. 17, 2001, now abandoned, the specificationof which is hereby incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention refers to a charged internal combustion engine.

2. Description of the Related Art

Internal combustion engines with turbochargers, as commonly known, usethe energy contained in the exhaust and convert it into mechanicalenergy in an exhaust turbine to power a turbo compressor, whichincreases the pressure of the air supplied to the internal combustionengine. To accomplish this, turbocharging can occur in one or moresteps.

In DE 198 37 978 A1, a two step turbocharging is disclosed, where atleast two turbines are attached in the exhaust section, each of whichpower a turbo compressor. The exhaust turbines are connected in seriesas high and low pressure level. First, the exhaust flows through thehigh pressure turbine and then through the low pressure turbine. Thecharge air is first compressed by the low pressure compressor and thenby the high pressure compressor and, in certain cases after cooling bypassing through a heat exchanger, is supplied to the fresh gas side ofthe internal combustion engine. As the RPM of the internal combustionengine is increased, compression is increasingly shifted towards asingle stage which occurs exclusively in the low pressure compressor. Incomparison to one-step compression, charging is already possible at lowengine speeds with such a two-step charging process, but the turbineoperation, and therefore indirectly the compressor operation, is limitedby the energy contained in the exhaust. That means that the unburned gasconducted into the internal combustion engine can only be compressed alittle, especially with lower speeds. Without boost the internalcombustion engine creates weak torque, which leads to poor accelerationwhen used in a motor vehicle.

SUMMARY OF THE INVENTION

The invention is concerned with the task of improving an internalcombustion engine of the type disclosed in the precharacterizing portionof claim 1, so that it can generate high torque even at low RPM, andthus making stationary torque available more rapidly at partial load. Indoing so, a high charge pressure should build up early on, which canmatch the requirements of the internal combustion engine.

Based on the invention, this task is solved by connecting a supplementalcompressor, which has a drive which is independent from the workingmedium cycle of the internal combustion engine, arranged in parallel orin series with the turbocharger.

In an especially beneficial embodiment, the supplemental compressor isdriven by an electric motor, and the supplemental compressor isconnected with the turbocharger in series. The supplemental compressoris beneficially arranged upstream of the turbocharger, in front of theturbocharger in the direction of flow.

In a further developed embodiment, a closing or switching means islocated between the supplemental compressor and the compressor of theturbocharger. Working with an electronic control device for the electricmotor and the closing or switching means and power electronics requiredto support the electric motor, the supplemental compressor supplementsthe turbocharger in operational conditions in which the power taken fromthe exhaust flow is not sufficient or not present.

In a beneficial execution, the supplemental compressor and thecompressor of the turbocharger are matched to each other in such amanner, that a comparably wide characteristic diagram or power curveresults. The compression ratio of the supplemental compressor and thecompression ratio of the turbocharger compressor are multiplied at eachoperating point.

In a further developed execution, the electric motor is regulated basedon the boost pressure output of the turbocharger in relation to theprescribed boost pressure curve, so that the supplemental compressor isswitched off when the required boost pressure is reached by theturbocharger. However, a predetermined excess or reserve of the boostpressure may be maintained in unsteady operating phases.

In a special execution, the supplemental compressor and the turbochargertake in air via different intake sections, where the closing-switchingmeans guarantees that the air which is pre-compressed by thesupplemental compressor can only flow in the direction of theturbocharger, or when the supplemental compressor of the turbocharger isturned off, cannot conduct air through the supplemental compressor anymore. In an advantageous execution of the invention, a charge cooler orheat exchanger is provided between the turbocharger and the internalcombustion engine. This decreases the thermal stress of the componentson the one hand, and on the other decreases the specific volume of thecompressed air which had experienced heating during compression in thesupplemental compressor and turbocharger, thus resulting in an increasein specific volume. By cooling and densifying the air, the charged massof the combustion engine is increased, which results in a considerableincrease in power.

Because the power of the supplemental compressor can be operatedindependently from the internal combustion engine, a further advantageof the invention is that the supplemental compressor also functions as asecondary air pump to conduct the air in the catalytic converter toincrease the conversation rate of the catalytic converter in a coldcondition.

Through an appropriate design of the turbine, a decrease in the exhaustgas counterpressure is made possible. The execution of the invention isobviously possible with various structural shapes of turbochargers(turbochargers with waste gate or flap or also a charger with variableturbine geometry). The use of multi-stage turbochargers is asconceivable as the use of several supplemental compressors, where theconnection could occur not only in series but also in parallel. Severalheat exchangers could also be used beneficially. If needed, thesupplemental compressor and the turbocharger can intake from the sameintake section. A possible bypass with a switch means makes it possibleto detour the exhaust gas side of the turbocharger. In order to reducethe amount of nitrogen oxide emission through the exhausts coming fromthe internal combustion engine, an exhaust gas recirculation system(EGR) can be used, which draws in an amount of exhaust gas from a engineexhaust conduit to a point upstream from the turbine of theturbocharger, and conducts it into an engine intake conduit (DE 41 20055 A1).

In an especially beneficial execution of the invention, the supplementalcompressor can be incorporated in an assembly of the internal combustionengine. In doing so it is possible to either incorporate only thesupplemental compressor into the assembly or also additional componentsor aggregates, such as the switching and/or closing means in front ofand behind the supplemental compressor, if necessary, required throttlemeans or even the drive for the supplemental compressor. When puttingthe supplemental compressor in the intake pipe assembly, it isbeneficial to integrate the supplemental compressor in the intake pipeor to build it onto the intake pipe. In a further developed execution,the spiral guide around the compressor wheel can be directly formed onthe intake pipe. When mounting the supplemental compressor drive at theintake pipe (or at the internal combustion engine or the body), it isbeneficial to provide a vibration decoupling fastener in order tomitigate the vibration loads of the internal combustion engine'sstimulus.

In another beneficial execution of the invention, the cylinder headassembly contains the supplemental compressor. For this, thesupplemental compressor can be integrated or mounted in the cylinderhead or in the cylinder head cover. Formation of the spiral guide aroundthe compressor wheel is possible directly on the cylinder head. Whenmounting the supplemental compressor drive at the cylinder head,vibration decoupling is beneficially executed.

Other beneficial executions of the invention provide for integration orbuilding on the supplemental compressor in/at the air filter casing oralso in/at the exhaust train. Here also, in a further developedexecution, the spiral guide around the compressor wheel is formeddirectly at the air filter casing or in the exhaust train, and thesupplemental compressor drive is mounted with vibration decoupling. In afurther developed execution of the invention, when arranging thecomponents in the exhaust, these are thermally decoupled, i.e.connecting using a flange with minimal heat conducting capabilities orshielding using a heat shield to minimize the temperature stress on thecomponents.

It is beneficial to connect the heat produced by the drive using acoolant circuit corresponding with the supplemental compressor drive tocool the supplemental compressor drive when necessary.

In an especially beneficial execution of the invention, theswitching/closing/or throttle means located in front of or behind thesupplemental compressor could also be integrated or built into thefollowing components: intake pipe/cylinder head cover/air filtercasing/exhaust train. In a further developed execution—if thesupplemental compressor is used as a secondary air pump—the secondaryair conduit can also be integrated into or mounted into the mentionedcomponents. The same is possible for the exhaust gas recirculationconduit and the engine ventilation. In the same way, it is possible tointegrate the on board diagnostic (OBD) monitor and the sensors in thesame assemblies. The turbocharger compressor can also be integrated orbuild into the components in an especially preferred execution.

A very compact and cost-effective construction is achieved with thementioned executions where the supplemental compressor is integrated inthe assemblies of the internal combustion engine, so that, for example,when used in motor vehicles, the supplemental compressor barely requiresadditional space compared to the conventional internal combustionengines. Because especially short pipes (air, gas and coolant pipes) areused with these integral constructions, waste and leak risks areminimized.

In an especially beneficial execution, the invention includes control ofthe supplemental compressor. In a first execution, this control isintegrated into the internal combustion engine's control. In a furtherdeveloped form of the invention, the electronic control of thesupplemental compressor is separate from the internal combustionengine's control, where especially advantageous parameters of the engineperformance conditions represent an input quantity of the controlelectronics.

In another beneficial execution of the invention, the internalcombustion engine's control is split into partial or subcomponentsystems, wherein the control of the supplemental compressor is connectedto the entire system as a partial system. The individual partial systemscommunicate with each other using a bus system (CAN-Bus). Benefits ofthis subdivision are the simple monitoring and programming of thepartial system.

In an especially beneficial execution of the invention, the vehicle'sentire system is split into partial systems (system islands). Thecontrol of the supplemental compressor is incorporated in such a partialsystem; the partial systems communicate with each other using a bussystem (CAN-Bus). An advantage of this execution is the possibility tomatch the individual systems with each other optimally, so that theprimary goal is optimally adjusting the fuel consumption for the poweroutput as currently or instantaneously necessary for the internalcombustion engine. Additional advantages are the simple monitoring andprogramming of the partial systems and the possibility to add additionalcomponents of control without great effort.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred executions of the invention are explained in references to theattached drawings. They show in:

FIG. 1 a schematic representation of an internal combustion engine withone-step turbocharging and an supplemental compressor powered by anelectric motor in a first execution based on the invention.

FIG. 2 a schematic of an internal combustion engine with simpleturbocharging and supplemental compressor with secondary air channel,turbine bypass and exhaust return.

FIG. 3 a schematic of an internal combustion engine with simpleturbocharging and supplemental compressor with secondary air channel,turbine bypass and exhaust return, with the supplemental compressorintegrated into the intake pipe assembly.

FIG. 4 a schematic of an internal combustion engine with simpleturbocharging and supplemental compressor with secondary air channel,turbine bypass and exhaust return, with the supplemental compressorintegrated into the cylinder head assembly.

FIG. 5 a schematic of an internal combustion engine with simpleturbocharging and supplemental compressor with secondary air channel,turbine bypass and exhaust return, with the supplemental compressorintegrated into the air filter casing assembly.

FIG. 6 a schematic of an internal combustion engine with simpleturbocharging and supplemental compressor with secondary air channel,turbine bypass and exhaust return, with the supplemental compressorintegrated into the exhaust train assembly.

FIG. 7 a schematic of a control for the supplemental compressorintegrated into the engine control.

FIG. 8 a schematic of a control for the supplemental compressor separatefrom the engine control.

FIG. 9 a schematic of an engine control split into partial systems,including the control of the supplemental compressor as a partialsystem.

FIG. 10 a schematic of a vehicle entire system split into partialsystems, including the control of the supplemental compressor as apartial system.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an internal combustion engine 1, which on the fresh gasside 2 is connected to the compressor of a turbocharger 3 and asupplemental compressor 4. The supplemental compressor 4 is connected tothe turbocharger compressor 3 in series, and arranged, in the flowdirection, in front of the turbocharger compressor 3. The supplementalcompressor 4 is powered by an electric motor 5. The turbine 7 of theturbocharger is connected to the internal combustion engine 1 on theexhaust side 6. A closing or switching means 8 is arranged between thesupplemental compressor 4 and the turbocharger compressor 3. Using theswitch means 8, the turbocharger compressor 3 can draw from its ownintake area 9 as well as from the supplemental compressor 4. Thesupplemental compressor 4 draws from the intake area 10. If necessary,two air mass measurers or meters as well as two filters are provided.

FIG. 2 shows an internal combustion engine with simple turbocharging andan electrically powered supplemental compressor, where the main designcorresponds with FIG. 1. A closing means 11 is arranged in flowdirection behind the supplemental compressor 4, parallel to the closingor switching means 8, with which the mass flow in the secondary airchannel 12 can be controlled. A charge cooler 13 is arranged in flowdirection behind the turbocharger compressor 3, which cools the freshcompressed gas before entry into the internal combustion engine 1.Operation without turbocharging is possible with a bypass 14, whichdiverts exhaust gas to the exhaust side of the turbine 7 of theturbocharger. The switching means 15 controls the mass flow, which isconducted on the fresh gas side using the exhaust return 16.

FIG. 3 shows an internal combustion engine with all components from FIG.2. In this execution, the intake pipe assembly 18 includes the intakepipe 17, a throttle valve 19 and a supplemental compressor 4, arrangedsequentially going in the upstream direction. In addition, drive 5 ofthe supplemental compressor 4 and the switching or throttling means 20are arranged in front of and behind the supplemental compressor 4 in theintake pipe assembly 18. Supplemental compressor 4 and turbochargercompressor 3 draw raw air from the same intake area 9, in which the airmass meter 21 and air filter 22 are connected.

FIG. 4 shows the schematic of an internal combustion engine in which thecylinder head assembly 23 includes the supplemental compressor 4, itsdrive 5 and the closing or switching means. Integrating the supplementalcompressor 4 and mounting the drive 5 in the or at the cylinder headcover 1.1 is beneficial.

FIG. 5 shows the schematic of an internal combustion engine, in whichthe air filter casing assembly 24 incorporates the supplementalcompressor, its drive 5, the closing or switching means 20 which arearranged in front of the supplemental compressor 4 in flow direction,the air mass measurer 21 and the air filter 22.

FIG. 6 shows the schematic of an internal combustion engine, in whichthe exhaust train assembly 25 incorporates the supplemental compressor4, its drive 5, compressor 3 and turbine 7 of the turbocharger, thecharge cooler 13 and the closing or switching means 20.

FIG. 7 shows the schematic of an internal combustion engine, in whichthe control 40 of the supplemental compressor is integrated into theengine control 41.

FIG. 8 shows an internal combustion engine with a control 40 of thesupplemental compressor which is separately executed from the enginecontrol 41, where the parameters of the engine operational condition areinput quality of the control electronics of the supplemental compressor.

FIG. 9 shows the schematic of an engine control split into partialsystems, where, for example, the partial system of control 40 of thesupplemental compressor, the control of the partial system 42 of theintake pipe, of the partial system 43 of the injection and the partialsystem 44 of the air filter are represented. Additional partial systemsare indicated. The partial systems communicate with each other using thebus system 45 (CAN-bus).

FIG. 10 shows the schematic of a vehicle entire system split intopartial systems, where, for example the partial system 40 of the controlof the supplemental compressor, the partial system 46 (drive train), thepartial system 47 (ABS), the partial system 48 (chassis), the partialsystem 49 (passenger compartment) and the partial system 50 for heatingare represented. The partial systems communicate with each other usingthe bus system 45 (CAN-bus).

Reference Number List

-   -   1 internal combustion engine    -   2 fresh gas side    -   3 turbocharger compressor    -   4 supplemental compressor    -   5 electric motor    -   6 exhaust gas side    -   7 turbine    -   8 switch means    -   9 intake area    -   10 intake area    -   11 closing means    -   12 secondary air channels    -   13 charge cooler    -   14 bypass    -   15 adjusting means    -   16 exhaust return    -   17 intake pipe    -   18 intake pipe assembly    -   19 throttle valve    -   20 switching means    -   21 air mass measurer    -   22 air filter    -   23 cylinder head assembly    -   24 air filter casing assembly    -   25 exhaust train assembly    -   40 controller    -   41 engine control    -   42 partial system for the intake pipe    -   43 partial system for the injection    -   44 partial system for the air filter    -   45 bus system    -   46 partial system for the drive train    -   47 ABS    -   48 partial system for the chassis    -   49 partial system for the passenger compartment        -   partial system for the heating

1. A charged internal combustion engine (1) including: (a) at least onestage of charging by a turbocharger (3); (b) at least one supplementalcompressor (4) connected to the turbocharger; (c) an air filterassembly, wherein the air filter assembly includes the supplementalcompressor (4); (d) an electric motor (5) drive for the supplementalcompressor (4); and (e) at least one closing (11) or switching (8) meansprovided between the supplemental compressor (4) and the turbocharger(3), wherein an electronic control device (40) is present to regulateoperation of the supplemental compressor (4) and the closing (11) orswitching (8) means.
 2. The charged internal combustion engine (1) as inclaim 1, wherein the supplemental compressor is integrated in an airfilter casing.
 3. The charged internal combustion engine (1) as in claim1, wherein the supplemental compressor is mounted on an air filtercasing.
 4. The charged internal combustion engine (1) of claim 1,wherein the control of the supplemental compressor (4) is a subsystem inthe central internal combustion engine control (41).
 5. The chargedinternal combustion engine (1) of claim 4, wherein, wherein the partialsystems are connected to each other with a bus system (45).
 6. Thecharged internal combustion engine (1) of claim 1, wherein the controlmeans for the supplemental compressor (4) is separate from the internalcombustion engine control (41).
 7. The charged internal combustionengine (1) as in claim 6, wherein the parameters monitored as to theengine operational condition provide an input value for the controlelectronics.
 8. The charged internal combustion engine (1) of claim 1,wherein the control of the supplemental compressor (4) is a subsystem ofthe vehicle system.
 9. The charged internal combustion engine (1) as inclaim 8, wherein the partial systems are connected to each other with abus system (45).